Chamber sensor port, chamber and electron beam processor

ABSTRACT

A pressure sensing port includes an inner block airtightly attached to an inside of a port attachment opening and having a first through hole extending along the axis of the port attachment opening and an intermediate block airtightly attached adjacently to an axially outer surface of the inner block. The intermediate block has a second hole extending through axially in a position where the second through hole is not superposed on the first through hole and communicating with the first through hole through a gap formed between the inner block and the intermediate block. An outer block is airtightly attached between the inner block and intermediate block and has a third through hole extending axially in a position where the third through hole is not superposed on both the first and the second through hole and communicating with the first and the second through hole.

FIELD OF THE INVENTION

The present invention relates to a chamber sensor port and a chamber foruse in a semiconductor manufacturing apparatus and the like, and anelectron beam processor.

BACKGROUND OF THE INVENTION

In general, a semiconductor manufacturing apparatus provided with avacuum chamber serving as a processing room includes a pressure sensorinstalled on an outside of a wall of the chamber. The pressure sensor isconnected to the vacuum chamber via a chamber pressure sensing portairtightly installed through the wall of the chamber in order to measureand manage a pressure or a vacuum level inside the chamber. In the priorart, a partition type shielding plate, which blocks contaminants, isprovided in front of the chamber pressure sensing port so as to preventthe contaminants generated in the vacuum chamber from getting into andadhering to the pressure sensor through the chamber pressure sensingport.

However, when a semiconductor manufacturing apparatus for irradiatingelectron beams onto a substrate to be processed (a semiconductor wafer)in a vacuum chamber, e.g., an electron beam annealing equipment, outputsaccelerated electrons of high energy into the chamber, X-rays aregenerated and scattered in the chamber to cause problems of being leakedout of the vacuum chamber through the chamber pressure sensing port.

It is generally known that a material with a narrow lattice spacing or aheavy material such as lead, stainless steel (SUS), lead-containingglass (containing 75% PbO) and the like can shield or attenuate theX-rays. However, even with the partition type shielding plate made ofthe material with a narrow lattice spacing, it is difficult toeffectively shield a conventional pressure sensing port from the X-raysscattering in random directions. Further, the port opening area shouldbe reduced in order to increase the degree of shielding or covering,thereby deteriorating a pressure sensing response characteristic.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide achamber sensor port, a chamber, and an electron beam processor, whichare capable of guaranteeing a satisfactory physical quantity sensingresponse characteristic and, at the same time, blocking radioactive rayscompletely.

In accordance with a first aspect of the present invention, there isprovided a chamber sensor port which connects a sensor for measuring aphysical quantity inside a chamber to an inside of the chamber, thesensor being installed on an outside of a wall of the chamber, thechamber sensor port including: a port attachment opening formed byrunning through the wall of the chamber; a first block airtightlyinstalled at an inside of the port attachment opening and including oneor more first through holes running through in a direction of an axis ofthe port attachment opening; and a second block airtightly installed atthe inside of the port attachment opening, the second block beingdisposed adjacent to an axially outer surface of the first block andincluding one or more second through holes running through in thedirection of the axis of the port attachment opening, the second throughholes being disposed at locations not overlapping with those of thefirst through holes and communicating with the first through holesthrough a gap formed between the first and the second block.

In accordance with the present invention, the chamber can be smoothlyconnected to the sensor through a communication path formed along thefirst and the second through holes and the gap between the first blockand the second block. Since the second through holes run through in thedirection of the axis of the port attachment opening with the positionsof the second through holes being disposed at locations not overlappingwith those of the first through holes, the communication path forms alabyrinth. Accordingly, because of a double layer block structure havingthe labyrinth formed by the first and the second blocks, at least one ofthe first and the second blocks can block radioactive rays getting intothe chamber sensor port from the chamber in random directions.

It is preferable that the first and the second blocks are made ofmaterials capable of blocking radioactive rays (e.g., X-rays). In thiscase, it is preferable that each of the first and the second blocks hasa sheet thickness capable of blocking radioactive rays (e.g., X-rays)incident thereto from an inside of the chamber. For example, each of thefirst and the second blocks can be made of stainless steel having asheet thickness greater than or equal to 8 mm. In that case, at leastone of the first and the second blocks can effectively block theradioactive rays invading from the chamber into the chamber sensor portin random directions.

In accordance with another preferred embodiment of the presentinvention, there is provided a chamber sensor port further including athird block airtightly installed between the first block and the secondblock and including one or more third through holes running through inthe direction of the axis of the port attachment opening, the thirdthrough holes being disposed at locations not overlapping with those ofthe first and the second through holes and communicating with the firstand the second through holes through a gap formed between the firstblock and the third block and a gap formed between the second block andthe third block, respectively.

With the above-described configuration, a side of the chamber can besmoothly connected to a side of the sensor through a communication pathformed along the first, the second, and the third through holes and allgaps formed between the second block and the third block and between thefirst block and the third block. Since the third through holes runthrough in the direction of the axis of the port attachment opening withthe positions of the third through holes being disposed at locations notoverlapping with those of the first and the second through holes, thecommunication path forms a labyrinth. With a triple layer blockstructure of the first, the second, and the third block, at least twoblocks can cooperatively block radioactive rays (e.g., X-rays) invadingfrom the chamber into the chamber sensor port in the random direction.Thus, a size of the chamber sensor port can be reduced by minimizing asheet thickness of layer of each block, while securing a sufficientlylarge opening area due to the labyrinth structure of the triple layerblock. At this time, it is preferable that each of the first, thesecond, and the third blocks is made of materials capable of blockingradioactive rays (e.g., X-rays) and each block has a sheet thicknessgreater than or equal to a half of a sheet thickness capable of blockingradioactive rays (e.g., X-rays) incident thereto from an inside of thechamber. Accordingly, it is possible to effectively block radioactiverays, e.g., X-rays, getting into the chamber sensor port.

Moreover, each of the first, the second, and the third block can be madeof stainless steel having a sheet thickness greater than or equal to 4mm, thereby maintaining a sum of sheet thicknesses of each block in anaxial direction to be greater than 8 mm at any place in thecommunication path from the chamber to the sensor. For example,radioactive rays such as X-rays can be effectively blocked by stainlesssteel having a sheet thickness greater than or equal to 8 mm.

Besides, it is preferable that each block, more preferably every block,in the chamber sensor port is made of stainless steel capable ofeffectively blocking radioactive rays without causing environmentalproblems.

It is also preferable that a first pipe airtightly attached to an insideof the port attachment opening with the first pipe being disposedadjacent to an inside of the sidewall of the chamber. Accordingly,radioactive rays invading from the chamber can be blocked withoutleaking outwards and then can be completely blocked, to thereby achievea multi layer block structure. The first pipe preferably has a diameterallowing the first through holes to be therewithin. For example, bydisposing a first through hole with an axis thereof being coincidentwith that of the port attachment opening in the first block, the firstpipe can be disposed, with the axis thereof being coincident with thatof the first through hole. And also, if the first pipe is airtightlyattached to the first block through a center axis fitting ring aroundwhich an O-ring is placed, a satisfactory sealing can be generated. Thefirst pipe can be made of stainless steel.

Still further, the second pipe extending to the sensor can be airtightlyattached to an outer sidewall of the chamber of the second block andhave a diameter allowing the second through holes to be therewithin.Moreover, the center axis fitting ring around which the O-ring is placedcan be installed between the second pipe and the second block.

In accordance with a second aspect of the present invention, there isprovided a chamber including a chamber sensor port which connects asensor for measuring a physical quantity inside a chamber to an insideof the chamber, the sensor being installed on an outside of a wall ofthe chamber, the chamber sensor port including: a port attachmentopening formed by running through the wall of the chamber; a first blockairtightly installed at an inside of the port attachment opening andincluding one or more first through holes running through in a directionof an axis of the port attachment opening; and a second block airtightlyinstalled at the inside of the port attachment opening, the second blockbeing disposed adjacent to an axially outer surface of the first blockand including one or more second through holes running through in thedirection of the axis of the port attachment opening, the second throughholes being disposed at locations not overlapping with those of thefirst through holes and communicating with the first through holesthrough a gap formed between the first and the second block.

In accordance with a third aspect of the present invention, there isprovided an electron beam processor including a chamber sensor portwhich connects a sensor for measuring a physical quantity inside achamber to an inside of the chamber, the sensor being installed on anoutside of a wall of the chamber, the chamber sensor port including: aport attachment opening formed by running through the wall of thechamber; a first block airtightly installed at an inside of the portattachment opening and including one or more first through holes runningthrough in a direction of an axis of the port attachment opening; and asecond block airtightly installed at the inside of the port attachmentopening, the second block being disposed adjacent to an axially outersurface of the first block and including one or more second throughholes running through in the direction of the axis of the portattachment opening, the second through holes being disposed at locationsnot overlapping with those of the first through holes and communicatingwith the first through holes through a gap formed between the first andthe second block.

Because the double layer block structure having the labyrinth is alsoformed by the first and the second blocks in accordance with the secondand the third preferred embodiments of the present invention, at leastone of the first and the second blocks can block radioactive raysinvading from the chamber into the chamber sensor port in randomdirections.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cross sectional view of a processor to which the presentinvention can be applied;

FIG. 2 illustrates an arrangement of electron beam tubes disposed at aceiling portion of a chamber in the processor of FIG. 1;

FIG. 3 describes exemplary projected patterns formed on a surface of asubstrate to be processed by electron beams emitted from the electronbeam tubes in the processor of FIG. 1;

FIG. 4 depicts a cross sectional view of a chamber pressure sensingport;

FIGS. 5A and 5B present a configuration of an inner block disposed inthe chamber pressure sensing port, wherein FIG. 5A is a plan view of theinner block seen at a pressure sensor side and FIG. 5B is a crosssectional view of the inner block;

FIGS. 6A and 6B represent a configuration of an intermediate blockdisposed in the pressure sensing port, wherein FIG. 6A is a plan view ofthe intermediate block seen at the pressure sensor side and FIG. 6B is across sectional view of the intermediate block;

FIGS. 7A and 7B offer a configuration of an outer block disposed in thepressure sensing port, wherein FIG. 7A is a plan view of the outer blockseen at the pressure sensor side and FIG. 7B is a cross sectional viewof the outer block;

FIG. 8 provides a schematic view of a configuration of through holes,gaps and the like in a triple layer block structure; and

FIG. 9 sets forth numerical values of the through holes, the gaps andthe like in the triple layer block structure of FIG. 8.

Explanation about Reference Numbers

10 chamber 26 pressure sensing port 28 vacuum gauge 44 port assembly 46tube 48 inner block 50 intermediate block 52 outer block 54 tube 55O-ring 56 center axis fitting ring 59 O-ring 60 Center axis fitting ring

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, an electron beam processor in accordance with a preferredembodiment of the present invention will be described in detail withreference to the accompanying drawings.

Referring to FIG. 1, there is illustrated an electron beam processor(hereinafter, referred to as the “processor”) adopting a pressuresensing port that is an example of the chamber sensor port in accordancewith the present invention. The processor irradiates electron beams ontothe entire top surface (a surface to be processed) of a substrate to beprocessed, e.g., a semiconductor wafer W, in a vacuum processing room,to thereby perform a predetermined process.

The processor has a chamber 10 as a processing room, wherein the chamber10 can be vacuum-sealed and has a box or a cylindrical shape havingclosed top and bottom surfaces. It is preferable that the chamber 10 ismade of, e.g., aluminum. A susceptor 14 is horizontally installed on asupport or supporting member 12 disposed on a central portion of abottom surface of the chamber 10. The susceptor 14 is formed by shaping,e.g., a carbon material or an aluminum compound such as AlN in the formof a circular plate and, further, includes therein a resistance heater16 serving as a heating device. A plurality of, e.g., three, throughholes 14 a are disposed at regular intervals in the susceptor 14. Alifter pin 17 is provided to be vertically movable through each of thethrough holes 14 a by an elevator (not shown) between a position higherthan the susceptor 14 (a wafer transferring position) and a positionlower than the susceptor 14 (a retracted position).

Attached airtightly to a sidewall of the chamber 10 are a processing gasnozzle 18 which serves as a gas supply unit for providing requiredprocessing gases (e.g., N₂, He, O₂, and H₂) into the chamber and a gatevalve 20 which is opened and closed when the semiconductor wafer W isloaded into or unloaded from the chamber.

An exhaust port 22 is provided at a periphery portion of the bottomsurface of the chamber 10 and is connected to a vacuum pump (not shown)via an exhaust path 24. An inner space of the chamber 10 can bedepressurized to a desired vacuum level by the vacuum pump. In order tomeasure a pressure as a physical quantity in the chamber 10, a pressuresensing port 26, which will be described later, is installed through thesidewall of the chamber 10, and a vacuum gauge 28 functioning as apressure sensor is attached to an end portion of the pressure sensingport 26.

A plurality of electron beam tubes 30 are installed at a ceiling portionof the chamber 10. Specifically, the electron beam tubes 30 aresubstantially uniformly spaced apart (in a substantially uniformdistribution density) over an almost entire ceiling portion of thechamber 10, e.g., as illustrated in FIG. 2 in order that electron beamscan be emitted to an entire upper surface (a surface to be processed) ofthe semiconductor wafer W loaded on the susceptor 14 from the ceilingsurface disposed directly thereabove. Each electron beam tube 30 has anemission window 32 attached to a bottom portion thereof, the emissionwindow 32 being of a rectangular shape and coated with a thin siliconfilm 34 capable of transmitting electron beams.

A filament 36 is installed in each electron beam tube 30. Electrons,which are generated from the filament 36 and accelerated in a beam shapeby using an accelerating electrode (not shown), get into the chamber 10through the corresponding emission window 32. The electron beams 38introduced into the chamber 10 are diverged to be irradiated onto thesemiconductor wafer W. During the process, X-rays are generated at thetime when accelerated electrons are emitted through the silicone film 34of each electron beam tube 30. The X-rays thus produced owing to thegeneration of the electron beams 38 are scattered in random directionsinside the chamber 10.

FIG. 2 illustrates an arrangement of nineteen electron beam tubes 30 andFIG. 3 depicts irradiation patterns 40 formed on a surface of thesemiconductor wafer W by the electron beams 38 emitted from therespective electron beam tubes 30. In this case, an arrangement of theelectron beam tubes 30 or a distance between the electron beam tubes 30and the susceptor 14 is determined such that irradiation patterns 40 ofa substantially circular shape abut each other substantially.

At the ceiling portion of the chamber, a cooling gas nozzle 41 isinstalled near the emission window 32 of each electron beam tube 30.Cooling gas, e.g., inert gas, sprayed from the cooling gas nozzles 41 isused for cooling the emission windows 32 heated by the electron beams38.

A process of the above-mentioned processor, e.g., a process forimproving a quality of a resist film, is executed as follows. First, thegate valve 20 installed on the sidewall of the chamber 10 is opened inorder to allow an external transfer arm (not shown) to load thesemiconductor wafer W into the chamber 10. Thereafter, the semiconductorwafer W is handed over to the lifter pins 17 above the susceptor 14, sothat the semiconductor wafer W is horizontally loaded on leading ends ofthe lifter pins 17. Then, the lifter pins 17 are lowered to transfer thesemiconductor wafer W on top of the susceptor 14. The top surface (asurface to be processed) of the semiconductor wafer W is provided withthe resist film uniformly coated thereon during a previous process.

Next, a processing gas, e.g., N₂ (concentration of O₂ being less than300 ppm), is fed into the processing gas nozzle 18 from a processing gassource (not shown). Meanwhile, the chamber 10 is evacuated by the vacuumpump (not shown) through the exhaust port 22 and the exhaust path 24, sothat inside of the chamber 10 can be maintained at a predeterminedvacuum level. Further, with heat generated from the resistance heater 16embedded in the susceptor 14 by the application of power thereto, thesemiconductor wafer W loaded on top of the susceptor 14 is heated up toa certain temperature (e.g., about 100° C.) within a range, e.g., fromroom temperature to 500° C.

In addition, each of the electron beam tubes 30 installed at the ceilingportion of the chamber 10 is operated to irradiate the electron beam 38of an acceleration energy ranging from 5 keV to 15 keV, e.g., 6 keV, onthe top surface (a surface to be processed) of the semiconductor wafer Wloaded on the susceptor 14 (a dose of 2 mC). As a result, a process forcuring or improving the resist film coated on the semiconductor wafer Wis carried out.

In the processor, a pressure of the depressurized space inside thechamber 10 is measured by the vacuum gauge 28 installed at the sidewallof the chamber 10 through the pressure sensing port 26, to therebycontrol pumping rate of the vacuum pump such that the measured pressureis equal to a preset value.

FIG. 4 presents a configuration of the pressure sensing port 26 inaccordance with the preferred embodiment of the present invention. Thepressure sensing port 26 has a port attachment opening 42, having aT-shaped cross section formed through the sidewall of the chamber 10,wherein a port assembly 44 capable of blocking X-rays and transmittingpressure is assembled in the port attachment opening 42.

The port assembly 44 includes a tube (pipe) 46 inserted from the insideof the chamber 10 into a small aperture portion 42 a of the portattachment opening 42; an inner block 48 positioned inside a largeaperture portion 42 b of the port attachment opening 42 and airtightlyattached to a bottom surface of the large aperture portion 42 b throughan O-ring 55; an intermediate block 50 positioned inside the largeaperture portion 42 b of the port attachment opening 42 and installedadjacent to an axially outer surface of the inner block 48; an outerblock 52 positioned inside the large aperture portion 42 b of the portattachment opening 42 and installed adjacent to an axially outer surfaceof the intermediate block 50; and a tube (pipe) 54 airtightly attachedto an axially outer surface of the outer block 52 at an outside of theport, attachment opening 42 (an outside of the chamber 10).

The inner block 48 is made of stainless steel, e.g., SUS304, SUS316 orSUS316L, and has a shape of generally circular plate as illustrated inFIGS. 5A and 5B. The inner block 48 includes one through hole 48 aextending through a central portion thereof along an axial direction anddepressed portions 48 b and 48 c formed on a top surface (an outersurface) and a bottom surface (an inner surface) thereof and havinguniform depths, respectively.

As shown in FIG. 4, the tube 46 is protruded axially from the smallaperture portion 42 a of the port attachment opening 42 into the largeaperture portion 42 b. The protrusion is formed in a stair shape, sothat the tube 46 has a thin flange portion 46 a of a smaller externaldiameter. The inner block 48 is coaxially attached to the flange portion46 a of the tube 46 through a KF (Klein Flange) fitting, e.g., a centeraxis fitting ring 56, around which an O-ring 55 is placed. Specifically,an external diameter of the tube 46 and that of the ring 56 are set tobe approximately equal to a diameter of the depressed portion 48 bformed on the bottom surface (the inner surface) of the inner block 48and the tube 46, the ring 56 and the inner block 48 are coaxiallydisposed. The O-ring 55 is inserted between a lower surface of the largeaperture portion 42 b and the bottom surface of the inner block 48. Adiameter of the through hole 48 a of the inner block 48 can be made tobe approximately equal to an inner diameter of the tube 46. The tube 46and the center axis fitting ring 56 may be made of stainless steel,e.g., SUS304, SUS 316 or SUS316L, while the O-ring 55 may be made offluoroelastomer, e.g., Baiton (a brand name).

The intermediate block 50 is made of stainless steel, e.g., SUS304,SUS316, or SUS316L, and formed in a shape of an approximately circularplate as illustrated in FIGS. 6A and 6B. The intermediate block 50 isprovided with a plurality of, e.g., four, through holes 50 a(circumferentially spaced apart at 90° intervals) running through aperipheral portion thereof in the axial direction. A depressed portion50 b having a uniform depth is provided on a top surface (an outersurface) of the intermediate block 50. A radius or a distance from acentral axis of the intermediate block 50 to each through hole 50 athereof can be considerably greater than a diameter of the through hole48 a of the inner block 48.

As shown in FIG. 4, the intermediate block 50 has a same externaldiameter as that of the inner block 48 and is coaxially loaded on aperipheral portion of the top surface (the outer surface) of the innerblock 48. A gap is provided between a bottom surface (an inner surface)of the intermediate block 50 and the top surface (the outer surface) ofthe inner block 48 by the presence of the depressed portion 48 c of theinner block 48. All the through holes 50 a of the intermediate block 50are open to the gap (the depressed portion 48 c) and communicates withthe through hole 48 a of the inner block 48 and a passageway of the tube46 via the gap (the depressed portion 48 c). What is important here isthat the through holes 50 a of the intermediate block 50 are positionedradially further outside of the through hole 48 a of the inner block 48from the central axis of the port attachment opening 42, so that thethrough holes 50 a do not overlap with the through hole 48 a.

The outer block 52 is made of stainless steel, e.g., SUS304, SUS316, orSUS316L, and formed in the shape of a cup upside-down as illustrated inFIGS. 7A and 7B. The outer block 52 includes a deep depressed portion 52a of a relatively large aperture at a bottom surface (an inner surface)thereof and a shallow depressed portion 52 b of a relatively smallaperture at a top surface (an outer surface) thereof. Further, the outerblock 52 is provided with a number of, e.g., four, through holes 52 c(circumferentially spaced apart at 90° intervals) axially runningthrough a peripheral portion of the depressed portion 52 b formed on thetop surface (the outer surface).

Referring back to FIG. 4, an outer diameter of the outer block 52 isdetermined such that the outer block 52 can be easily inserted into thelarge aperture portion 42 b of the port attachment opening 42 and adiameter of the depressed portion 52 a formed on the bottom surface (theinner surface) of the outer block 52 is determined such that the innerblock 48 and the intermediate block 50 can be easily inserted thereinto.Herein, a gap is provided between the bottom surface (the inner surface)of the outer block 52 and the top surface (the outer surface) of theintermediate block 50 due to the depressed portion 50 b of theintermediate block 50. The through holes 52 c of the outer block 52 areopen to the gap (the depressed portion 50 b) and communicate with thethrough holes 50 a of the intermediate block 50 via the gap (thedepressed portion 50 b). Herein, the through holes 52 c of the outerblock 52 are located between the through holes 50 a of the intermediateblock 50 and the through hole 48 a of the inner block 48 in radialdirections from the central axis of the port attachment opening 42, sothat each of the through holes 52 c, 50 a, and 48 a is prevented frombeing overlapped with each other.

A plural number of bolt through holes 52 d are circumferentiallyprovided around an outer periphery portion of the outer block 52 atregular intervals. Meanwhile, tapped holes 10 a are provided atpositions corresponding to those of the bolt through holes 52 d of theouter block 52, on the bottom surface of the large aperture portion 42 bof the port attachment opening 42 for accommodating therein the outerblock 52. Bolts 58 are inserted into the bolt through holes 52 d andscrewed into the tapped holes 10 a, so that the triple block structureof the inner block 48, the intermediate block 50, and the outer block 52can be fixed as a single body to the chamber 10 and the O-ring 55 iscompressively deformed between the inner block 48 and the bottom surfaceof the large aperture portion 42 b to yield an airtight sealing. It isalso possible that the three blocks 48, 50, and 52 are combined bywelding to form a sub-assembly of a singly body.

Inserted between the outer block 52 and the tube 54 is the KF fitting,e.g., a center axis fitting ring 60, around which an O-ring 59 isattached. To be more specific, a bottom portion of the tube 54 isbroadened outwardly in radial directions, to form a flange portion 54 a.And, the O-ring 59 is inserted between a bottom portion of the flangeportion 54 a and the outer block 52. The center axis fitting ring 60 isinserted between the depressed portion 52 b formed on the top surface(the outer surface) of the outer block 52 and a depressed portion formedat a bottom part of a passageway of the tube 54, with a surface of thecenter axis fitting ring 60 along the axial direction being coincidentwith those of the depressed portion 52 b and the depressed portion ofthe tube 54 along the axial direction. The tube 54 and the center axisfitting ring 60 may be made of stainless steel, e.g., SUS304, SUS316, orSUS316L, while the O-ring 59 may also be made of fluoroelastomer, e.g.,the Baiton (the brand name).

The flange portion 54 a of the tube 54 is covered with a ring-shapedrestraint member 62. Plural bolt through holes 62 a arecircumferentially disposed around a periphery portion of the restraintmember 62 at regular intervals. Similarly, tapped holes 52 e areprovided at positions corresponding to those of the bolt through holes62 a, on the top surface (the outer surface) of the outer block 52 onwhich the restraint member 62 is placed. By screwing bolts 64 into thetapped holes 52 e, the tube 54 is fixed on the outer block 52 throughthe restraint member 62. Further, the O-ring 59 is compressivelydeformed between the flange portion 54 a of the tube 54 and the outerblock 52, to thereby provide the airtight sealing.

The vacuum gauge (a pressure sensor) 28 is airtightly attached to theother end portion of the tube 54. The vacuum gauge 28 may be either avoltage vacuum gauge or a partial pressure vacuum gauge or, e.g., acapacitive vacuum gauge, a Pirani vacuum gauge or the like. The vacuumgauge 28 generates an electric signal PS, as a pressure sensing signalaccording to a pressure in the tube 54.

The above-described pressure sensing port 26 has a path (a communicationpath) formed between the chamber 10 and the vacuum gauge 28.Specifically, the chamber 10 can communicate with the vacuum gauge 28through the path running sequentially through the passageway of the tube46, the central through hole 48 a of the inner block 48, the gap (thedepressed portion 48 c of the inner block 48) formed between the innerblock 48 and the intermediate block 50, the peripheral through holes 50a of the intermediate block 50, the gap (the depressed portion 50 b ofthe intermediate block 50) provided between the intermediate block 50and the outer block 52, the through holes 52 c disposed around thecenter of the outer block 52, and the passageway of the tube 54.Therefore, the pressure in the chamber 10 is smoothly transmitted to thevacuum gauge 28 through the above-mentioned path (the communicationpath). The three blocks 48, 50, and 52 form a three-step labyrinthinside the path. The labyrinth confers sufficiently large conductance togas species and is able to have a large opening area without affecting apressure sensing response.

Considering X-rays scattering inside the chamber 10, X-rays entering orintruding from an inside of the chamber into the port assembly 44 can becompletely obstructed or blocked by the triple layer blocks 48, 50 and52.

For example, X-rays straightly entering the passageway of the tube 46can be multi-blocked by the intermediate block 50 and the outer block 52even if the X-rays pass through the through hole 48 a of the inner block48. Further, X-rays intruding into the tube 46 by being reflected can bemulti-blocked by at least two blocks among the inner block 48, theintermediate block 50, and the outer block 52. In addition, X-raysgetting into an inside of the port assembly 44 through the chamber wall(aluminum) around the tube 46 can also be multi-blocked by at least twoblocks among the inner block 48, the intermediate block 50, and theouter block 52.

In general, stainless steel having a sheet thickness of about 8 mm isable to nearly completely block X-rays emitted at the time of generatingaccelerated electrons having an accelerated voltage of about 10–15 KeV.Accordingly, it is preferable that a sum of thicknesses of the innerblock 48, the intermediate block 50, and the outer block 52 in the axialdirection is set to be greater than or equal to at least 8 mm at everyportion in the path formed between the chamber 10 and the vacuum gauge28. For instance, it is also preferable that a sheet thickness of eachof the inner block 48, the intermediate block 50, and the outer block 52in the axial direction is set to be greater than or equal to 4 mm. Withthe triple layer block structure having the aforementioned sheetthicknesses, X-rays intruding from any directions inside the chamber 10can be completely blocked by the stainless steel (SUS) having athickness of greater than or equal to 8 mm. For example, since the sumof the sheet thicknesses of the intermediate block 50 and the outerblock 52 is greater than or equal to 8 mm, X-rays even passing throughthe through hole 48 a of the inner block 48 can be completely blocked bythe intermediate block 50 and the outer block 52.

In addition, by way of configuring the tube 46 disposed inside the wallof the chamber 10 to be made of stainless steel (SUS), X-rays gettinginto the tube 46 can be guided to the triple layer block structuredisposed therein without leaking outwards and then can be completelyblocked.

Once the X-rays are introduced into stainless steel (SUS), they areattenuated while passing therethrough and generates secondary andtertiary X-rays due to reflection. However, in case X-rays generated dueto accelerated electrons of about 10–15 KeV are reflected three times,it is attenuated down to a level (less than or equal to 0.6 μSv/h), thelevel being considered to be almost ignorable, so that the presence ofquaternary X-rays may not be considered.

FIGS. 8 and 9 present exemplary numerical values of through holes andgaps, which are important factors besides the sheet thickness of theblocks, in the triple layer block structure including the blocks 48, 50,and 52 in accordance with the preferred embodiment of the invention. InFIG. 9, “hole” and “*” indicate the through holes 48 a, 50 a or 52 c anda multiplication sign, respectively.

In the preferred embodiment, as illustrated in FIG. 9, a sum of areas ofholes in the inner block 48, i.e., Sa* Na, is designed to be equal to orsmaller than i) ii), iii), and iv): i) is smaller one among La* Na* Gaband Lb* Nb* Gab, which respectively represent hole periphery areas ofholes (through holes) 48 a and 50 a between the inner block 48 and theintermediate block 50; ii) is a sum of areas of holes of theintermediate block 50, i.e., Sb* Nb; iii) is a smaller one among Lb* Nb*Gbc and Lc* Nc* Gbc, which respectively represent hole periphery areasof holes (through holes) 50 a and 52 c between the intermediate block 50and the outer block 52; and iv) is a sum of areas of holes of the outerblock 52, i.e., Sc* Nc.

The inner block 48, the intermediate block 50, and the outer block 52 inthe pressure sensing port 26 of the preferred embodiment correspond to afirst, a second, and a third block of the present invention,respectively. Further, the through holes 48 a, 50 a and 52 c correspondto the first, the second, and the third through holes of the presentinvention, respectively.

While the preferred embodiment of the invention has been described withreference to the accompanying drawings, the present invention is notlimited thereto. It would be understood by those skilled in the art thatvarious changes and modifications may be made without departing from thespirit of the invention as defined in the claims and such changes andmodifications should be construed as belonging to the scope of thepresent invention.

For example, the pressure sensing port 26 of the present invention isnot limited to have the triple layer block structure including theinner, the intermediate, and the outer block 48, 50, and 52; but can bea double layer or a quadruple layer block structure. For instance, theinner block 48 and the outer block 52 may be placed adjacent to eachother by omitting the intermediate block 50.

With the double or the quadruple layer block structure, X-rays can becompletely blocked. However, in case of the double layer blockstructure, a sheet thickness of each block in the axial direction shouldbe greater than or equal to 8 mm in order to set the sum of the sheetthicknesses of the blocks in the axial direction to be greater than orequal to at least 8 mm in every portion in the path between the chamber10 and the vacuum gauge 28. Accordingly, a net thickness of the sum ofall the blocks becomes greater than or equal to 16 mm, so that the sizeof the port assembly 44 becomes enlarged. In case of the above-describedtriple layer block structure, it is sufficient to set the thickness ofeach block to be greater than or equal to 4 mm, so that it is possibleto reduce the net thickness of the sum of all the blocks to 12 mm,enabling to reduce the size of the port assembly 44. Meanwhile, in caseof a n-tuple layer structure with n being equal to or greater than 4, alabyrinth structure becomes complicated, so that it is difficult todesign or manufacture the port assembly 44. Further, an aperture ratiois decreased, so that a pressure sensing response characteristic isdeteriorated. Therefore, the triple layer block structure is moreadvantageous.

Furthermore, each part of the port assembly 44 can be made of materialother than stainless steel (SUS), e.g., lead or lead-containing glass,to obtain the X-ray blocking effect. Since, however, lead-basedmaterials have a pollution problem, it is practical and advantageous tomanufacture each part of the port assembly 44 by using stainless steel(SUS).

Moreover, it is to be appreciated that the above-described chamber 10 isa mere example to which the present invention is applied. The chambersensor port of the present invention can be applied to any chamberrequiring the prevention of radioactive rays other than X-rays frombeing leaked out. A sensor attached to the chamber sensor port inaccordance with the present invention can be any sensor capable ofdetecting a desired physical quantity in the chamber through the chambersensor port, other than the above-described pressure sensor. Theconfiguration of the parts of the processor in accordance with thepreferred embodiment is also an example of the present invention. Asubstrate to be processed in accordance with the present invention maybe an LCD substrate, a CD substrate, a glass substrate, a photomask, aprint substrate, and the like, without being limited to a semiconductorwafer.

By using the above-described chamber sensor port of the presentinvention, it is possible to guarantee a satisfactory physical quantitysensing response characteristic and, at the same time, completely blockradioactive rays.

INDUSTRIAL APPLICABILITY

The present invention can be applied to the chamber sensor portinstalled in a semiconductor manufacturing apparatus or the like and,particularly, to the chamber sensor port for measuring a physicalquantity in the chamber in which radioactive rays are dispersed.

1. A chamber sensor port which connects a sensor for measuring aphysical quantity inside a chamber to an inside of the chamber, thesensor being installed on an outside of a wall of the chamber, thechamber sensor port comprising: a port attachment opening formed byrunning through the wall of the chamber; a first block airtightlyinstalled at an inside of the port attachment opening and including oneor more first through holes running through in a direction of an axis ofthe port attachment opening; a second block airtightly installed at theinside of the port attachment opening, the second block being disposedadjacent to an axially outer surface of the first block and includingone or more second through holes running through in the direction of theaxis of the port attachment opening, the second through holes beingdisposed at locations not overlapping with those of the first throughholes and communicating with the first through holes through a gapformed between the first and the second block; a third block airtightlyinstalled between the first block and the second block and including oneor more third through holes running through in the direction of the axisof the port attachment opening, the third through holes being disposedat locations not overlapping with those of the first and the secondthrough holes and communicating with the first and the second throughholes through a gap formed between the first block and the third blockand a gap formed between the second block and the third block,respectively.
 2. The chamber sensor port of claim 1, wherein the thirdblock is made of a material blocking radioactive rays.
 3. The chambersensor port of claim 2, wherein each of the first, the second, and thethird block has a thickness greater than or equal to one half of a sheetthickness capable of blocking the radioactive rays incident thereto fromthe inside of the chamber.
 4. The chamber sensor port of claim 3,wherein the radioactive rays are X-rays.
 5. The chamber sensor port ofclaim 1, wherein each of the first, the second, and the third block ismade of stainless steel having a sheet thickness greater than or equalto 4 mm.
 6. A chamber sensor port which connects a sensor for measuringa physical quantity inside a chamber to an inside of the chamber, thesensor being installed on an outside of a wall of the chamber, thechamber sensor port comprising: a port attachment opening formed byrunning through the wall of the chamber; a first block airtightlyinstalled at an inside of the port attachment opening and including oneor more first through holes running through in a direction of an axis ofthe port attachment opening; and a second block airtightly installed atthe inside of the port attachment opening, the second block beingdisposed adjacent to an axially outer surface of the first block andincluding one or more second through holes running through in thedirection of the axis of the port attachment opening, the second throughholes being disposed at locations not overlapping with those of thefirst through holes and communicating with the first through holesthrough a gap formed between the first and the second block, wherein afirst tube is airtightly installed in the port attachment opening, thefirst tube being disposed adjacent to a surface of the first blockfacing an inner surface of the wall of the chamber.
 7. The chambersensor port of claim 6, wherein the first tube has a diameter allowingall the first through holes to open thereto.
 8. The chamber sensor portof claim 7, wherein the first block has one first through hole coaxiallyplaced with the port attachment opening and the first tube is coaxiallyplaced with the first through hole.
 9. The chamber sensor port of claim6, wherein the first block is airtightly attached to the inside of theport attachment opening through an O-ring.
 10. The chamber sensor portof claim 6, wherein the first tube is made of stainless steel.
 11. Achamber sensor port which connects a sensor for measuring a physicalquantity inside a chamber to an inside of the chamber, the sensor beinginstalled on an outside of a wall of the chamber, the chamber sensorport comprising: a port attachment opening formed by running through thewall of the chamber; a first block airtightly installed at an inside ofthe port attachment opening and including one or more first throughholes running through in a direction of an axis of the port attachmentopening; and a second block airtightly installed at the inside of theport attachment opening, the second block being disposed adjacent to anaxially outer surface of the first block and including one or moresecond through holes running through in the direction of the axis of theport attachment opening, the second through holes being disposed atlocations not overlapping with those of the first through holes andcommunicating with the first through holes through a gap formed betweenthe first and the second block, wherein a second tube extending to thesensor is airtightly attached to a surface of the second block adjacentto an outer surface of the wall of the chamber.
 12. The chamber sensorport of claim 11, wherein the second tube has a diameter allowing allthe second through holes to be open thereto.
 13. The chamber sensor portof claim 11, wherein a center axis fitting ring around which an O-ringis attached is installed between the second tube and the second block.14. An electron beam processor comprising a chamber sensor port whichconnects a sensor for measuring a physical quantity inside a chamber toan inside of the chamber, the sensor being installed on an outside of awall of the chamber, the chamber sensor port including: a portattachment opening formed by running through the wall of the chamber; afirst block airtightly installed at an inside of the port attachmentopening and including one or more first through holes running through ina direction of an axis of the port attachment opening; and a secondblock airtightly installed at the inside of the port attachment opening,the second block being disposed adjacent to an axially outer surface ofthe first block and including one or more second through holes runningthrough in the direction of the axis of the port attachment opening, thesecond through holes being disposed at locations not overlapping withthose of the first through holes and communicating with the firstthrough holes through a gap formed between the first and the secondblock.